Dopant and conductive polymer material therewith

ABSTRACT

A conductive polymer material can exhibit good heat resistance and good moisture resistance, in which the conductive polymer comprises as a dopant at least one of aromatic sulfonic acid derivatives represented by general formula 1:  
                 
         wherein at least one of R 1  to R 6  represents a sulfonic acid group having a counter cation selected from the group consisting of a hydrogen ion, an alkali metal ion, an alkaline-earth ion and a transition metal ion belonging to groups 8 to 10 in the periodic table; and the remaining R 1  to R 6 , which may be the same or different, represent hydrogen, alkyl having four or less carbon atoms or phenyl; or any two or more of R 1  to R 6  may be combined together to form an aromatic or aliphatic ring; and general formula 2:  
                 
   wherein at least one of R 7  to R 10  represents a sulfonic acid group having a counter cation selected from the group consisting of a hydrogen ion, an alkali metal ion, an alkaline-earth ion and a transition metal ion belonging to groups 8 to 10 in the periodic table; and the remaining R 7  to R 12 , which may be the same or different, represent hydrogen, alkyl having four or less carbon atoms or phenyl; or any two or more of R 7  to R 10  may be combined together to form an aromatic or aliphatic ring.

FIELD OF THE INVENTION

This invention relates to a novel aromatic sulfonic acid derivativedopant which is applicable to a conductive polymer material; aconductive polymer material containing the dopant; and a solidelectrolytic capacitor using the polymer material. In particular, thisinvention relates to a conductive polymer material with good heatresistance and moisture resistance which is suitable for manufacturing asolid electrolytic capacitor, and a solid electrolytic capacitor inwhich the polymer material is used as a cathode conductive material.

BACKGROUND OF THE INVENTION

In recent years with the advance in electronics technology, novelelectronic materials have been developed. In particular, remarkabletechnological innovation has been achieved in the area involving highperformance organic materials. Even if the scope of view is restrictedto the conductive materials alone, there have been developed conductivepolymer materials produced by way of doping electron-conjugated polymerssuch as polyacetylene, polyparaphenylene, polypyrrole, and polyanilinewith some electron acceptable compounds as the dopant. And, there areeven cases in which newly developed materials have been actuallyindustrialized as a capacitor electrode material, a battery electrodematerial and an antistatic material.

However, for extending industrial applicability of these conductivepolymer materials, significant problems involving environmentalstability such as heat resistance and moisture resistance must besolved, besides further improvement in conductivity.

For solving these problems encountered in industrialization, we haveprovided, in terms of environmental stability, a π-electron conjugatedpolymer material comprising an m-sulfobenzamide derivative as a dopant,exhibiting both higher conductivity and improved heat resistance inJapanese Laid-open Patent Publication 2000-204074.

For example, we have found that polypyrrole doped with m-sulfobenzamideexhibits considerably slow reduction in a conductivity even when beingplaced in the air at 150° C. and can maintain a high conductivity of 100S/cm or more.

Polypyrrole doped with m-sulfobenzamide, however, rapidly loses itsconductivity when the atmosphere contains moisture at a hightemperature. Thus, for extending industrial applicability of aconductive polymer material, it is essential that the material exhibitsimproved stability under the moisture-containing atmosphere at a hightemperature, i.e., under the conditions of a high temperature and a highhumidity.

Thus, an objective of this invention is to provide a dopant which endowsa π-electron conjugated polymer material with a higher conductivitywhich can be retained even under the environmental conditions of a hightemperature and a high humidity; a conductive polymer material with goodheat resistance and good moisture resistance; and a solid electrolyticcapacitor comprising the polymer material.

SUMMARY OF THE INVENTION

Namely, this invention relates to a dopant consisting of at least one ofaromatic sulfonic acid derivatives represented by general formulas 1 and2; a conductive polymer material containing the dopant which exhibitsgood heat resistance and good moisture resistance; and a solidelectrolytic capacitor comprising the polymer material.

-   -   wherein at least one of R¹ to R⁶ represents a sulfonic acid        group having a counter cation selected from the group consisting        of a hydrogen ion, an alkali metal ion, an alkaline-earth ion        and a transition metal ion belonging to groups 8 to 10 in the        periodic table; and the remaining R¹ to R⁶, which may be the        same or different, represent hydrogen, alkyl having four or less        carbon atoms or phenyl; or any two or more of R¹ to R⁶ may be        combined together to form an aromatic or aliphatic ring.    -   wherein at least one of R⁷ to R¹⁰ represents a sulfonic acid        group having a counter cation selected from the group consisting        of a hydrogen ion, an alkali metal ion, an alkaline-earth ion        and a transition metal ion belonging to groups 8 to 10 in the        periodic table; and the remaining R⁷ to R¹², which may be the        same or different, represent hydrogen, alkyl having four or less        carbon atoms or phenyl; or any two or more of R⁷ to R10 may be        combined together to form an aromatic or aliphatic ring.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In this invention, one or more aromatic sulfonic acid derivativesrepresented by general formula 1 and 2 above are used as a dopant.

In the aromatic sulfonic acid derivative represented by general formula1 or 2, a counter cation to a sulfonic acid group is a cation of anelement selected from hydrogen, alkali metals, alkaline earth metals andtransition metals belonging to groups 8 to 10 in the periodic table; forexample, hydrogen, lithium, sodium, potassium, rubidium, cesium,beryllium, magnesium, calcium, strontium, barium, iron, cobalt, nickel,ruthenium, rhodium, palladium, osmium, iridium and platinum ions,preferably hydrogen, sodium, potassium and iron(III) ions.

Examples of the aromatic sulfonic acid derivative represented by generalformula 1 include aromatic sulfonic acid derivatives such as

-   2-sulfo-1,8-naphthalic anhydride,-   3-sulfo-1,8-naphthalic anhydride,-   4-sulfo-1,8-naphthalic anhydride,-   3,5-disulfo-1,8-naphthalic anhydride,-   3,6-disulfo-1,8-naphthalic anhydride,-   4,5-disulfo-1,8-naphthalic anhydride,-   2-methyl-4-sulfo-1,8-naphthalic anhydride,-   5-methyl-4-sulfo-1,8-naphthalic anhydride,-   6-methyl-4-sulfo-1,8-naphthalic anhydride,-   7-methyl-4-sulfo-1,8-naphthalic anhydride,-   5-methyl-3-sulfo-1,8-naphthalic anhydride,-   6-methyl-3-sulfo-1,8-naphthalic anhydride,-   7-methyl-3-sulfo-1,8-naphthalic anhydride,-   2-ethyl-4-sulfo-1,8-naphthalic anhydride,-   5-ethyl-4-sulfo-1,8-naphthalic anhydride,-   6-ethyl-4-sulfo-1,8-naphthalic anhydride,-   7-ethyl-4-sulfo-1,8-naphthalic anhydride,-   5-ethyl-3-sulfo-1,8-naphthalic anhydride,-   6-ethyl-3-sulfo-1,8-naphthalic anhydride,-   7-ethyl-3-sulfo-1,8-naphthalic anhydride,-   2-n-propyl-4-sulfo-1,8-naphthalic anhydride,-   5-n-propyl-4-sulfo-1,8-naphthalic anhydride,-   6-n-propyl-4-sulfo-1,8-naphthalic anhydride,-   7-n-propyl-4-sulfo-1,8-naphthalic anhydride,-   5-n-propyl-3-sulfo-1,8-naphthalic anhydride,-   6-n-propyl-3-sulfo-1,8-naphthalic anhydride,-   7-n-propyl-3-sulfo-1,8-naphthalic anhydride,-   2-isopropyl-4-sulfo-1,8-naphthalic anhydride,-   5-isopropyl-4-sulfo-1,8-naphthalic anhydride,-   6-isopropyl-4-sulfo-1,8-naphthalic anhydride,-   7-isopropyl-4-sulfo-1,8-naphthalic anhydride,-   5-isopropyl-3-sulfo-1,8-naphthalic anhydride,-   6-isopropyl-3-sulfo-1,8-naphthalic anhydride,-   7-isopropyl-3-sulfo-1,8-naphthalic anhydride,-   2-n-butyl-4-sulfo-1,8-naphthalic anhydride,-   5-n-butyl-4-sulfo-1,8-naphthalic anhydride,-   6-n-butyl-4-sulfo-1,8-naphthalic anhydride,-   7-n-butyl-4-sulfo-1,8-naphthalic anhydride,-   5-n-butyl-3-sulfo-1,8-naphthalic anhydride,-   6-n-butyl-3-sulfo-1,8-naphthalic anhydride,-   7-n-butyl-3-sulfo-1,8-naphthalic anhydride,-   2-isobutyl-4-sulfo-1,8-naphthalic anhydride,-   5-isobutyl-4-sulfo-1,8-naphthalic anhydride,-   6-isobutyl-4-sulfo-1,8-naphthalic anhydride,-   7-isobutyl-4-sulfo-1,8-naphthalic anhydride,-   5-isobutyl-3-sulfo-1,8-naphthalic anhydride,-   6-isobutyl-3-sulfo-1,8-naphthalic anhydride,-   7-isobutyl-3-sulfo-1,8-naphthalic anhydride,-   2-tert-butyl-4-sulfo-1,8-naphthalic anhydride,-   5-tert-butyl-4-sulfo-1,8-naphthalic anhydride,-   6-tert-butyl-4-sulfo-1,8-naphthalic anhydride,-   7-tert-butyl-4-sulfo-1,8-naphthalic anhydride,-   5-tert-butyl-3-sulfo-1,8-naphthalic anhydride,-   6-tert-butyl-3-sulfo-1,8-naphthalic anhydride,-   7-tert-butyl-3-sulfo-1,8-naphthalic anhydride,-   2-phenyl-4-sulfo-1,8-naphthalic anhydride,-   5-phenyl-4-sulfo-1,8-naphthalic anhydride,-   6-phenyl-4-sulfo-1,8-naphthalic anhydride,-   7-phenyl-4-sulfo-1,8-naphthalic anhydride,-   5-phenyl-3-sulfo-1,8-naphthalic anhydride,-   6-phenyl-3-sulfo-1,8-naphthalic anhydride,-   7-phenyl-3-sulfo-1,8-naphthalic anhydride,-   3-sulfo-1,9-anthracenedicarboxylic anhydride,-   4-sulfo-1,9-anthracenedicarboxylic anhydride,-   10-sulfo-1,9-anthracenedicarboxylic anhydride,-   3-sulfo-1,10-phenanthrenedicarboxylic anhydride,-   4-sulfo-1,10-phenanthrenedicarboxylic anhydride, and-   3-sulfoacenaphthylene-5,6-dicarboxylic anhydride, as well as alkali    metal salts, alkaline earth metal salts and transition metal salts    belonging to groups 8 to 10 in the periodic table, preferably sodium    salts, potassium salts and iron(III) salts, of the aromatic sulfonic    acid derivatives.

Preferable examples include aromatic sulfonic acid derivatives such as

-   2-sulfo-1,8-naphthalic anhydride,-   3-sulfo-1,8-naphthalic anhydride,-   4-sulfo-1,8-naphthalic anhydride,-   3,5-disulfo-1,8-naphthalic anhydride,-   3,6-disulfo-1,8-naphthalic anhydride,-   4,5-disulfo-1,8-naphthalic anhydride,-   2-methyl-4-sulfo-1,8-naphthalic anhydride,-   5-methyl-4-sulfo-1,8-naphthalic anhydride,-   6-methyl-4-sulfo-1,8-naphthalic anhydride,-   7-methyl-4-sulfo-1,8-naphthalic anhydride,-   5-methyl-3-sulfo-1,8-naphthalic anhydride,-   6-methyl-3-sulfo-1,8-naphthalic anhydride,-   7-methyl-3-sulfo-1,8-naphthalic anhydride,-   3-sulfo-1,9-anthracenedicarboxylic anhydride,-   4-sulfo-1,9-anthracenedicarboxylic anhydride and-   10-sulfo-1,9-anthracenedicarboxylic anhydride, as well as sodium,    potassium and iron(III) salts of the aromatic sulfonic acid    derivatives.

More preferable examples include 3-sulfo-1,8-naphthalic anhydride and4-sulfo-1,8-naphthalenic anhydride as well as sodium, potassium andiron(III) salts of the aromatic sulfonic acid derivatives.

Examples of the aromatic sulfonic acid derivative represented by generalformula 2 include aromatic sulfonic acid derivatives such as

-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5,7-disulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6,8-disulfonic acid,-   1-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   1-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   1-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   3-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   3-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   3-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   3-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   5-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   5-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   5-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   6-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   6-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   6-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   7-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   7-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   7-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   8-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   8-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   8-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   1,5-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   1,5-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid, a-   1,5-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   1,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   1,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   1,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   1,7-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   1,7-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   1,7-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   1,8-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   1,8-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   1,8-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   3,5-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   3,5-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   3,5-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   3,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   3,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   3,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   3,7-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   3,7-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   3,7-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   3,8-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   3,8-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   3,8-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   5,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   5,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   5,7-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   5,7-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   0,5,8-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   5,8-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   6,7-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   6,7-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   6,8-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   6,8-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   7,8-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   7,8-dimethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   1-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   1-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   1-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   3-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   3-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   3-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   3-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   5-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   5-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   5-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   6-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   6-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   6-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   7-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   7-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   7-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   8-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   8-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   8-ethyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-n-propyl-2,4-dioxo-1,2,3,4-tetrahydro quinazoline-5-sulfonic acid,-   1-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   1-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   3-n-propyl-2,4-dioxo-1,2,3,4-tetrahydro quinazoline-5-sulfonic acid,-   3-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   3-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   3-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   5-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   5-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   5-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   6-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   6-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   6-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   7-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   7-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   7-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   8-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   8-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   8-n-propyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   1-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   1-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   3-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   3-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   3-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   3-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   5-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   5-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   5-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   6-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   6-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   6-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   7-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   7-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   7-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   8-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   8-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   8-isopropyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   1-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   1-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   3-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   3-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   3-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   3-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   5-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   5-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   5-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   6-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   6-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   6-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   7-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   7-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   7-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   8-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   8-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   8-n-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   1-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   1-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   3-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   3-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   3-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   3-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   5-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   5-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   5-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   6-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   6-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   6-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   7-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   7-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   7-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   8-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   8-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   8-isobutyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   1-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   1-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   1-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   3-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   3-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   3-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-1-sulfonic    acid,-   3-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   5-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   5-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   5-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   6-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   6-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   6-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   7-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   7-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   7-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic    acid,-   8-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic    acid,-   8-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic    acid,-   8-tert-butyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic    acid,-   1-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   1-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   1-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   3-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   3-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   3-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   3-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   5-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   5-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   5-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   6-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   6-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   6-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   7-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   7-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   7-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   8-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   8-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   8-phenyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1,3-dioxo-1,2,3,4-tetrahydro-benzo[f]quinazoline-5-sulfonic acid,-   1,3-dioxo-1,2,3,4-tetrahydro-benzo [f]quinazoline-6-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydro-benzo[g]quinazoline-5-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydro-benzo[g]quinazoline-10-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydro-benzo[h]quinazoline-5-sulfonic acid and-   2,4-dioxo-1,2,3,4-tetrahydro-benzo[h]quinazoline-6-sulfonic acid, as    well as alkali metal salts, alkaline earth metal salts and    transition metal salts belonging to groups 8 to 10 in the periodic    table, preferably sodium, potassium and iron(III) salts, of the    aromatic sulfonic acid derivatives.

Preferable examples include aromatic sulfonic acid derivatives such as

-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5,7-disulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6,8-disulfonic acid,-   1-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   1-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   1-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   1-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   3-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   3-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   3-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   3-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   5-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   5-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   5-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   6-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   6-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid,-   6-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   7-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   7-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   7-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid,-   8-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   8-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid and-   8-methyl-2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid, as    well as sodium, potassium and iron(III) salts, of the aromatic    sulfonic acid derivatives.

More preferable examples include aromatic sulfonic acid derivatives suchas

-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-5-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-6-sulfonic acid,-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-7-sulfonic acid and-   2,4-dioxo-1,2,3,4-tetrahydroquinazoline-8-sulfonic acid, as well as    sodium, potassium and iron(III) salts, of the aromatic sulfonic acid    derivatives.

Aromatic sulfonic acid derivatives represented by general formulas 1 or2 can be used alone or in combination. They may be further used incombination with other dopants.

An aromatic sulfonic acid derivative represented by general formula 1 or2 may be prepared by, for example, a compound represented by generalformula 6 or 7 with an appropriate sulfonating agent such as sulfuricacid, fuming sulfuric acid, sulfur trioxide, sulfur trioxide-pyridinecomplex and amidosulfuric acid.

-   -   wherein at least one of R¹ to R⁶ represents hydrogen and the        others, which can be the same or different, represent hydrogen,        alkyl having four or less carbon atoms or phenyl; or appropriate        two or more of R¹ to R⁶ may be combined together to form an        aromatic or aliphatic ring.    -   wherein at least one of R⁷ to R¹⁰ represents hydrogen and the        remaining R⁷ to R¹², which can be the same or different,        represent hydrogen, alkyl having four or less carbon atoms or        phenyl; or appropriate two or more of R⁷ to R¹⁰ may be combined        together to form an aromatic or aliphatic ring.

As regards the synthesis via sulfonation described above, there is noparticular limitation to the reaction conditions. For instance, thereaction ratio of the compound represented by general formula 6 or 7 asa starting material (hereinafter, referred to as a sulfonized material)to the sulfonating agent, is generally 1:1 to 200 (molar ratio). It isnot necessary to use a reaction solvent in this sulfonation. If used,any solvent may be used insofar as it is capable of dissolving thesulfonized material and the sulfonating agent and, furthermore, does notget sulfonated itself. Examples of such solvents include dichloroethane,carbon tetrachloride and dioxane.

There is no particular limitation to the reaction temperature, insofaras it provides a proper reaction rate while avoiding abrupt heatgeneration causing progress of side reactions and avoiding decompositionof the sulfonized material and the reaction product aromatic sulfonicacid derivative. Generally, the reaction is carried out at a temperatureof 0 to 150° C. Employing such reaction conditions, the desired productcan be prepared at a high yield.

An aromatic sulfonic acid derivative according to this invention may beutilized as a dopant for doping a π-electron conjugated polymer toprovide a conductive polymer material which exhibits electricconductivity over an extended period of time. The conductive polymer maybe any polymer having a π-electron conjugated molecular structure; forexample, conjugated polymers having at least one of a pyrrole, athiophene and a aniline structure represented by general formula 3, 4and 5, respectively, as a repeating unit.

-   -   wherein R¹³ and R¹⁴, which may be the same or different,        represent hydrogen or straight, cyclic or branched alkyl or        alkoxy having 1 to 20 carbon atoms; or they may be combined        together to form a ring; provided that the symbol “*” denotes        the position where the repeating unit is bonded.    -   wherein R¹⁵ and R¹⁶, which may be the same or different,        represents hydrogen or straight, cyclic or branched alkyl or        alkoxy having 1 to 20 carbon atoms; or they may be combined        together to form a ring; provided that the symbol “*” denotes        the position where the repeating unit is bonded.    -   wherein R¹⁷ to R²⁰, which may be the same or different,        represents hydrogen or straight, cyclic or branched alkyl or        alkoxy having 1 to 20 carbon atoms; or either R¹⁷ and R¹⁸ or R¹⁹        and R²⁰ may be combined together to form a ring; provided that        the symbol “*” denotes the position where the repeating unit is        bonded.

Among these, a polymer used is preferably a π-electron conjugatedpolymer having at least one of the repeating units represented bygeneral formulas 3, 4 and 5, particularly a polypyrrole π-electronconjugated polymer having the repeating unit represented by generalformula 3.

A π-electron conjugated polymer may be doped with a aromatic sulfonicacid derivative according to this invention by any conventionally commonprocess such as immersing the polymer in a solution of the aromaticsulfonic acid derivative, electrolytic oxidation polymerization usingthe aromatic sulfonic acid derivative as a supporting electrolyte, andchemical oxidation polymerization using a transition metal of thearomatic sulfonic acid derivative.

In the case of the immersion doping, a solvent used for dissolving thearomatic sulfonic acid derivative may be any solvent with adequatedissolving power; for example, water, acetonitrile, nitrobenzene andpropylene carbonate.

In the case of the electrolytic oxidation polymerization, doping can beaccomplished by applying a given current or potential to a solution ofan aromatic sulfonic acid derivative as a supporting electrolyte and arepeating-unit forming monomer. Examples of the repeating-unit formingmonomer include pyrrole, thiophene, aniline and derivatives thereof.

The solvent used for the polymerization reaction may be any solventwhich can dissolve the aromatic sulfonic acid derivative and arepeating-unit forming monomer; for example, water, dimethylformamide,acetonitrile, propylene carbonate and ethyleneglycol. The electrolyticoxidation polymerization can be carried out within a temperature rangeof −100 to 150° C., preferably 0 to 50° C., employing eitherconstant-current or potentiostatic electrolysis. The electrolyticoxidation polymerization is preferably carried out in an inert gasatmosphere such as nitrogen and argon.

As for the doping via the chemical oxidation polymerization, a salt ofthe aromatic sulfonic acid derivative with a transition metal complexhaving a conjugate base ligand is contacted with a monomer having arepeating unit which can form a polymer having a π-electron conjugatedmolecular structure in a solvent to simultaneously conduct doping andpolymerization. A central metal in the transition metal complex may be,for example, iron, cobalt or ruthenium, particularly iron. Thetransition metal complex is generally used in an amount of 1-10 mol to 1mol of the monomer.

The repeating-unit forming monomer may be selected from pyrrole,thiophene, aniline and derivatives thereof described above. The solventused in the reaction may be any solvent capable of dissolving the abovetransition metal complex and the monomer; for example, water, dimethylformamide, acetonitrile, tetrahydrofuran, propylene carbonate andethyleneglycol. A polymerization temperature is preferably 0 to 50° C.and a reaction period is preferably 1 to 48 hours. The polymerization isdesirably conducted in an atmosphere of an inert gas such as nitrogenand argon.

There will be described an application of a conductive polymer materialaccording to this invention to a cathode conductive material for a solidelectrolytic capacitor.

A solid electrolytic capacitor generally has a basic structure where ananode metal is connected to a cathode conductive material via adielectric layer, and each of the anode metal and the cathode conductivematerial has an electrode lead thereof.

The anode metal may be made of, for example, aluminum or tantalum,generally in the form of an optionally etched foil. A cathode conductivematerial is generally an inorganic or organic conductive material whichhas been processed into a film. On its surface, a metal cathode may beformed. Furthermore, a graphite layer may be formed between the cathodeconductive material and the metal cathode for improving contact of thecathode conductive material with the metal cathode. The dielectric layeris generally a layer of an oxide of the anode metal, and may be thusformed by oxidizing the surface of the anode metal, or alternatively byapplying a fluid containing the anode-metal oxide.

The solid electrolytic capacitor according to this invention comprisesthe conductive polymer material described above as a cathode conductivematerial, while the anode metal may be a commonly used material. Thesolid electrolytic capacitor comprising a cathode and an anode may haveany shape such as a cylinder and a dipping piece.

EXAMPLES

This invention will be more specifically described with reference to,but not limited to, Examples.

Reference Example 1 Preparation of 3-sulfo-1,8-naphthalic anhydride

In 500 mL four-necked flask was placed 200 mL of fuming sulfonic acid(30 wt % excess of sulfur trioxide). With stirring the fuming sulfonicacid, 100 g of 1,8-naphthalic anhydride was slowly added, and thenstirring was continued at 100° C. for 10 hours. Then, the reactionmixture was left overnight. The reaction mixture was poured into 200 gof ice to decompose unreacted fuming sulfonic acid. After standing, themixture precipitated a brown powder, which was then collected byfiltration with a glass filter. The brown solid obtained by filtrationwas added to 300 mL of acetone, and the mixture was stirred for washing.After washing, acetone was removed to give a solid, which was thendissolved in 150 mL of concentrated sulfuric acid. To the solution wasadded 75 g of ice to generate a precipitate, which was then filteredwith a glass filter, rinsed with 300 mL of acetone, and dried in vacuoat room temperature for 24 hours to give a solid (37.1 g).

An FD-MS spectrum (Nippon Denshi Co. Ltd., SX-102A) for the productconfirmed that the product was 3-sulfo-1,8-naphthalicanhydride(m/z=277). It was also confirmed by an NMR spectrum (Solvent:DMSO-d₆: 8.75 ppm (s, 1H), 8.65 ppm (s+d, 2H), 8.52 ppm (d, 1H) and 7.92ppm (t, 1H)).

Reference Example 2 Preparation of (1H,3H)-quinazolinedione MonosulfonicAcid

A process was conducted as described in Reference Example 1,substituting 2,4(1H,3H)-quinazolinedione for 1,8-naphthalic anhydride togive 128.5 g of 2,4(1H,3H)-quinazolinedione monosulfonic acid.

An FD-MS spectrum confirmed that the product was2,4(1H,3H)-quinazolinedione monosulfonic acid (m/z=241). It was alsoconfirmed by an NMR spectrum (Solvent: DMSO-d₆: 8.11 ppm (s, 1H), 7.83ppm (d, 1H) and 7.12 ppm (d, 1H)).

Reference Example 3 Preparation of Sodium Salt of2,4(1H,3H)-quinazolinedione Monosulfonic Acid

In 300 mL of pure water was dissolved 156.11 g of2,4(1H,3H)-quinazolinedione monosulfonic acid prepared in ReferenceExample 2. To the stirred mixture was added portionwise 41.13 g ofsodium carbonate. A white solid was precipitated. The precipitate wasfiltered and dried in vacuo at room temperature overnight to give 97.34g of sodium salt of 2,4(1H,3H)-quinazolinedione monosulfonic acid.

Reference Example 4 Preparation of Sodium Salt of 3-sulfo-1,8-naphthalicAnhydride

In 300 mL of pure water was dissolved 138.5 g of 3-sulfo-1,8-naphthalicanhydride prepared in Reference Example 1. To the stirred mixture wasadded portionwise 26.5 g of sodium carbonate. A white solid wasprecipitated. The precipitate was filtered and dried in vacuo at roomtemperature overnight to give 119.6 g of sodium salt of3-sulfo-1,8-naphthalic anhydride.

Example 1

To 200 mL of pure water was dissolved 5.56 g of 3-sulfo-1,8-naphthalicanhydride prepared in Reference Example 1 and 1.34 g of pyrrole, toprepare a reaction solution for electrolytic oxidation polymerization.

To the reaction solution was bubbled nitrogen gas for about 15 min toreplace the atmosphere with nitrogen. In the solution was then immersedtwo 4 cm square stainless 304 plates (separated by 1 cm) as a workingelectrode and a counter electrode. A constant current (1.25 mA/cm²) wasapplied for 40 min to conduct electrolytic oxidation polymerization.

The polypyrrole film PA formed on the electrode was rinsed with purewater and acetone, removed from the electrode and dried in vacuo for 12hours.

The conductivity of the obtained film PA was measured by a four probemethod to be 61 S/cm.

Then, after retaining the polypyrrole film PA at an elevated temperatureof 150° C. for 8 hours, its conductivity was re-measured to be 59 S/cm.

On the other hand, the polypyrrole film PA was immersed in pure water at90° C. for 13 hours. The polypyrrole film was picked up, dried in vacuoand its conductivity was measured. This film kept a good conductivity of53 S/cm.

Example 2

A polypyrrole film PB was prepared as described in Example 1,substituting 4.86 g of 2,4(1H,3H)-quinazolinedione monosulfonic acidprepared in Reference Example 2 for 3-sulfo-1,8-naphthalic anhydride.

Its conductivity of the film PB prepared was measured by a four probemethod to be 91 S/cm.

After being retained in the air at an elevated temperature of 150° C.for 8 hours, the conductivity of the polypyrrole film PB was measured bya four probe method to be 89 S/cm.

After being retained in pure water at 90° C. for 13 hours and then driedin vacuo, the polypyrrole film PB kept a conductivity of 90 S/cm.

Example 3

A polypyrrole film PC was prepared as described in Example 2,substituting 5.28 g of sodium salt of 2,4(1H,3H)-quinazolinedionemonosulfonic acid prepared in Reference Example 3 for2,4(1H,3H)-quinazolinedione monosulfonic acid.

The conductivity of the film PC prepared was measured by a four probemethod to be 86 S/cm.

After being retained in the air at an elevated temperature of 150° C.for 7 hours, the conductivity of the polypyrrole film PC was measured bya four probe method to be 85 S/cm.

After being retained in pure water at 90° C. for 7 hours and then driedin vacuo, the film PC kept a conductivity of 90 S/cm.

Example 4

A polypyrrole film PD was prepared as described in Example 1,substituting 5.98 g of sodium salt of 3-sulfo-1,8-naphthalic acidprepared in Reference Example 4 for 3-sulfo-1,8-naphthalic anhydride.

After being retained in pure water at 90° C. for 7 hours and then dried,the film PD kept a good conductivity substantially as was immediatelyafter its preparation.

Example 5

A poly-3,4-ethylenedioxythiophene film TA was prepared as described inExample 1, substituting 2.84 g of 3,4-ethylenedioxythiophene forpyrrole.

After being retained in pure water at 90° C. for 7 hours and then dried,the film TA kept a good conductivity substantially as was immediatelyafter its preparation.

Example 6

A polyaniline film AA was prepared as described in Example 1,substituting 1.84 g of aniline for pyrrole.

After being retained in pure water at 90° C. for 7 hours and then dried,the film AA kept a good conductivity substantially as was immediatelyafter its preparation.

Example 7

A poly-3,4-ethylenedioxythiophene film TB was prepared as described inExample 2, substituting 2.84 g of 3,4-ethylenedioxythiophene forpyrrole.

After being retained in pure water at 90° C. for 7 hours and then dried,the film TB kept a good conductivity substantially as was immediatelyafter its preparation.

Example 8

A polyaniline film AB was prepared as described in Example 2,substituting 1.84 g of aniline for pyrrole.

After being retained in pure water at 90° C. for 7 hours and then dried,the film AB kept a good conductivity substantially as was immediatelyafter its preparation.

INDUSTRIAL APPLICABILITY

An aromatic sulfonic acid derivative according to this invention can beused as a dopant for a conductive polymer. A conductive polymer materialprepared after doping exhibits a higher conductivity, improved heatresistance and higher hot-water resistance. The conductive polymermaterial thus prepared can be, therefore, utilized as a material for,e.g., a capacitor electrode or battery electrode.

1. A dopant comprising at least one of aromatic sulfonic acidderivatives represented by general formula 1:

wherein at least one of R¹ to R⁶ represents a sulfonic acid group havinga counter cation selected from the group consisting of a hydrogen ion,an alkali metal ion, an alkaline-earth ion and a transition metal ionbelonging to groups 8 to 10 in the periodic table; and the remaining R¹to R⁶, which may be the same or different, represent hydrogen, alkylhaving four or less carbon atoms or phenyl; or any two or more of R¹ toR⁶ may be combined together to form an aromatic or aliphatic ring; andgeneral formula 2:

wherein at least one of R⁷ to R¹⁰ represents a sulfonic acid grouphaving a counter cation selected from the group consisting of a hydrogenion, an alkali metal ion, an alkaline-earth ion and a transition metalion belonging to groups 8 to 10 in the periodic table; and the remainingR⁷ to R¹², which may be the same or different, represent hydrogen, alkylhaving four or less carbon atoms or phenyl; or any two or more of R⁷ toR¹⁰ may be combined together to form an aromatic or aliphatic ring. 2.The dopant as claimed in claim 1 wherein the counter cation to thesulfonic acid group in general formula 1 or 2 is selected from the groupconsisting of hydrogen, sodium, potassium and iron(III) ions.
 3. Thedopant as claimed in claim 2 wherein in the sulfonic acid derivativerepresented by general formula 1 or 2, all of R¹ to R¹² other than thesulfonic acid group having the counter cation represent hydrogen.
 4. Thedopant as claimed in claim 3 wherein the aromatic sulfonic acidderivative comprises an aromatic sulfonic acid derivative represented bygeneral formula
 1. 5. The dopant as claimed in claim 3 wherein thearomatic sulfonic acid derivative comprises an aromatic sulfonic acidderivative represented by general formula
 2. 6-9. (Canceled)
 10. Thedopant as claimed in claim 1 wherein in the sulfonic acid derivativerepresented by general formula 1 or 2, all of R¹ to R¹² other than thesulfonic acid group having the counter cation represent hydrogen. 11.The dopant as claimed in claim 10 wherein the aromatic sulfonic acidderivative comprises an aromatic sulfonic acid derivative represented bygeneral formula
 1. 12. The dopant as claimed in claim 2 wherein thearomatic sulfonic acid derivative comprises an aromatic sulfonic acidderivative represented by general formula
 1. 13. The dopant as claimedin claim 1 wherein the aromatic sulfonic acid derivative comprises anaromatic sulfonic acid derivative represented by general formula
 1. 14.The dopant as claimed in claim 10 wherein the aromatic sulfonic acidderivative comprises an aromatic sulfonic acid derivative represented bygeneral formula
 2. 15. The dopant as claimed in claim 2 wherein thearomatic sulfonic acid derivative comprises an aromatic sulfonic acidderivative represented by general formula
 2. 16. The dopant as claimedin claim 1 wherein the aromatic sulfonic acid derivative comprises anaromatic sulfonic acid derivative represented by general formula 2.